Airplane appliance



May 6 1924.

J. M. CLARK AIRPLANE APPLIANCE Filed Oct. 8. 1920 s Sheets-Sheet 1 May a, 1924. 1,493,022

' J. M. CLARK AIRPLANE APPLIANCE Filed Oct. 8, 1920 I5 Sheets-Sheet 5 Patented May 6, 1924.

UNITED STATES PATENT OFFICE.

. JOHN M. CLARK, OF EL PASO, TEXAS.

AIRPLANE APPLIANCE.

Application filed October 8, 1920. Serial No. 415,885.

To all whom it may concern:

Be it known that 1, JOHN M. CLARK, a citizen of the United States, residing at El Paso, in the county of El Paso and State of Texas, have invented certain new and useful case the wheels strike an obstacle, or a landing is made in unduly soft ground, or a brake applied to the wheels-the airplane has a tendency to nose over. This tendency is due to the fact that the wheels are so positioned that they become practically the'longitudinal balance point, leaving a comparatively small portion of the airplanes welght to be supported by the tail skid. Thus it .will be seen that when suddenly arrested, and the center of gravity being above the axle and only slightly to the rear thereof, the-moment of inertia of the planes weight set up in a forward direction of rotation around the axle is too great to be counteracted by'the weight normally borne by the tail skid, a nosing over is the result. To obviate this difficulty it isfproposed to provide a landing gear capable of being shifted by the pilot from his seat forward from the n0rmal,or take-off position. This shiftsthe center of gravity further to the rear of the axle putting a heavier weight upon the tail skid 40 thus necessitating a greater moment of inertia, due to a sudden arrest of the wheels, to cause the ship to nose over. Realizing the advantages of having the wheels well forward when makin a stall landing in a small, muddy or roug field and also when applying brakes it is of added importance that the present invention provides for the shifting of the landing gear to either a take-off or landing position or any intermediate point therebetween. I

The landing gear may also be used as a means of regulating fore and aft balance as it can be shift ed forward or to the rear in fllght thusasslsting the pilot to correct for nose heaviness or tail heaviness.

The at present preferred embodiment of my inventlon is'found in the specification;

and illustrated in the accompanying drawings in which:-

Fig. 1 is a side elevation of the shiftable landlng gear in its normal rearward posiion;

Fig. 2 is a side elevation in detail of the operating gear;

Fig. 3 is a view similar to that in Fig. 1-

showing more particularly the hand brake and operating means;

Fig. 4. is a bottom plan view of the landmg gear-showing in detail the system of ca les and pulleys operating the hand brake; -F1g. 5 is an enlarged vertical cross section through one of the wheels and the brake mechanism;

Fi 6 is an enlarged side elevation of the braking crank and operating cable; Fi 7 is a detail plan view of the yoke member and equalizing bar as shown in Fig. 3.

Referring to the drawings more particularly the device consists of sleeves, A fixedly secured to the top of each landing gear strut X, surrounding, and in slidable relation with, rods B secured to the fuselage Q, by means of members Y.

.Asindicated in Fig. 1 the wheels Z are in correct position for taking-off. C is a shaft, bracketed to two longrons just forward of the pilots seat. On this shaft are keyed two crank 'members D one near each end and connected by the rods E to rear landing gear struts just below the sleeve A. Also keyed on shaft C is a ratchet wheel F connected by a two way pawl H to the lever G. The operation of the lever G thus effects the shifting of the landing gear to either a forward or rearward position. The landing gear may be locked in any intermediate position by the rack V engaging the teeth of the gear F. After the wheels have been shifted. forward it is safe to apply the brake.

. As shown in Fig. 5, attached to each wheel by means of a clamping ring J is a'grooved brake drum 1. Keyed on, the axle is a crank carrier K connected by means of. a bolt to the crank L. A cable N is attached to the extreme end of the crank-L and leads over suitable pulleys to an equalizing bar 0.

As shown more clearly in Fig. 4 a spring T is attached to the center of the equalizing bar 0 and keeps the cables N, taut at all times. The bar 0 is connected to the brake lever P by the cables N guided by pulleys W and a yoke member R which is held taut by the spring S thus preventing any kinking of the cables. It isv essential that each wheel shall have the same brake pressure applied as will be readily seen and for this purpose the equalizing bar 0 is provided which equa-lizes the tension of each cable upon each brake band with respect to one another.

The hand brakelver P is pivoted just below its center and may be easily operated by the pilot while in his seat. Upon pulling the lever P to the rear, the crank L, by reason of its connection with the cable N causes the brake band M which is fitted in the channeled groove of the brake drum I to tighten about the latter and bring the wheels to a stop.

The operation is as follows: The pilot 3 wishing to make a slow or stall landing because of a small'or muddy field shiftshis landing gear to its most forward position and as soon as the wheels start to roll on the ground the brakes may be applied thereby bringing the ship to a full stop. Before taking-off, the pilot shifts the landing gear to a rearward position to avoid extreme tail-heaviness on the take-ofi' and to avoid undue wear on' and breakage of the 40 tail skid while taxying.

It is to be noticed that an added feature .of my invention is that vertical stability may be attained by shifting the weight of 'the landing gear towards the nose or towards the tail of the plane thus correcting for, nose-heaviness" or tail heaviness.

Havlng thus described my invention, I claim:

1. In combinatiofwith an aircraft fuse lage, a landing gear structure therefor located in advance of the :center of gravity of the craft and adapted to be slid in a fore and aft direction to a location still further 'forwzird, and means forshifting said land- --ing gear in such-direction.

2. In comblnation'with an aircraft fuselage, alanding gear structure therefor embodying wheels and struts, guiding means on theifuselage along which the landing gear structure is slidable longitudinally of the fuselage, and means operable from the fuselage for shifting the landing gear structure. 3. In an airplane, a fuselage,- a landing gear, means connecting said landing gear to said fuselage adapted to permitthe land- I one mg gear to be shifted longitudinally of the thereof and sleeves carried by said landing gear adapted to surround said bars insliding relation therewith for'the purpose specisaid landing gear,

fied, and means operable .from the pilots 5 seat for advancing or retracting the landing gear on said slidable connecting means.

5. In an airplane, a fuselage, a landing gear, means connecting said landing gear to said fuselage adapted to permit the landing gear to be shifted longitudinally of the fuselage, said means comprising bars rigidly attached to the fuselage longitudinally thereof and sleeves carried by said landing gear adapted to surround said bars in sliding relation therewith for the purpose specified, means operable from the pilots seat for advancing or retracting the landing gear on said slidable connecting means, and

means for locking the landing ear in any position to, which it may be shi ed.

6. In an aircraft, the combination, of a fuselage, a wheeled landing gear structure, means for sliding said structure in a fore and aft direction-relatively to the fuselage, and wheel brake mechanism.

7. In an aircraft, a landing gear embodying wheels, and means operable from the pilots seat for sliding said wheels forwardly to a position well in advance of'their normal supporting position.

.8. In combination in an airplane, a fuse lage,'a landing gear, means connecting said permit the landing gear to be shifted longi- 110 landing gear to said fuselage adapted to tudinally of the fuselage, said means comprising bars rigidly attached to the fuselage longitudinally thereof and sleeves carried by said landing gear adapted to, surround said bars in sliding relation therewith for the purpose specified, and brake means operatively connected to said landing gear.

9. In combination in an airplane, a fuselage, a landing gear, means connecting said landing gear to said fuselage ada ted to permit the landing gear to be shifte longitudinally of the fuselage, said means comprising bars rigidly attached to the fuselage longitudinally thereof and sleeves. carried by said landing gear adapted to surround said bars in sliding relation therewith for the purpose specified, means operable from the pilots seat for advancing or retracting the landing gear on said slidable connecting mal supporting position, br'akefmechanism means, and brake means operatively conincluding brake elements applicable to said nected to said landing gear. Wheels, and means for equalizing the brak- 10 10, In an aircraft, a landing gear eming pressure of said elements. 5 bodying wheels, means operable from the In testimony whereof I have afliized my pilots seat for shifting said wheels forsignature.

wardly to a position in advance of their nora JOHN M. CLARK. 

